[R] How to change several elements of an array simultaneously?

[Peter Dalgaard BSA]

Peter Holzer <holzer at stat.math.ethz.ch> writes:

> I have a matrix `m' and two vectors `rs' and `cs'. I want to change m at the
> positions (rs[1], cs[1]), (rs[2], cs[2]), ... to 1. Obviously I can do that by
> 
> > m[rs + (cs-1) * dim(m)[1]] <- 1
> 
> but I would just be interested whether I am missing a more "intuitive" way
> of doing that.

This one is probably a candidate for the title of "most often
overlooked feature":

    m[cbind(rs,cs)] <- 1

-- 
   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
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